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Showing results for tags 'astrodynamics'.
I am creating 2 spaceflight-related alternate histories which would include missions directly launched to Mercury. However, there has never been a direct mission to Mercury (all of them have used gravity assists), preventing me from using an existing launch and the synodic period to calculate their launch dates (the only method I know how to use). So, does anyone know any optimal launch dates for direct Mercury transfers?
This thread is for the discussion of Aldrin Cycler Ships. First of all, an introduction to the topic- since most readers on this forum are undoubtedly unfamiliar with the concept, and the last time I wrote about it (many months ago) I received a lot of responses from people who clearly had no idea what they were talking about... Please read ALL of the following first, before commenting, I would really appreciate it. None of these are that long, and are only meant to provide a preliminary introduction to the topic: https://en.m.wikipedia.org/wiki/Mars_cycler https://buzzald
If a spacecraft is travelling in a circular orbit around a planet with a gravitational parameter of G at radius R1, and wishes to make a 90 degree planes change to a circular orbit of R2, what is the optimal burn strategy? For example, a simple inclination burn followed by a circularization burn might be correct. If the gravity is very high, it might be correct to push the orbit far away from the planet do the plane change, and then come back. Since there are two burns, there are opportunities to spread the inclination change across both burns. How can an optimal split be made?
When entering the SOI of a planet, we'd like to start our retrograde burn as close to periapsis as possible and with a low periapsis. For craft with low TWR, this will result in inefficiency, because you must start the burn pretty far away. My suspicion is that the greater you are from the true anomaly of 0 (Pe = True Anomaly of 0 degrees) the less efficient it is. What is the equation that gives the efficiency of a finite burn compared to an equivalent impulse burn?